Cabbage Looper

The larva is smooth and pale green with thin whitish stripes running along the body, and it is narrower toward the head. Its looping gait, caused by having fewer prolegs than many caterpillars, is a reliable identification cue. The adult is a mottled greyish-brown moth with a small silvery marking on each forewing.

Feeding produces large, irregular holes, and the larvae and their green frass may be found in the heart of heads or among leaves. The looping movement distinguishes it from many other green caterpillars found on the same crops.

Females lay dome-shaped eggs singly on the foliage. Larvae develop through several instars, then pupate in a thin cocoon attached to the plant. Generations are short in warm weather and overlap, giving several per season, while in colder regions populations are often re-established each year by moths moving in from warmer areas.

Naturally occurring pathogens, including insect-specific viruses, and a range of parasitoids and predators frequently exert strong control on looper populations, which is important context for management decisions.

Young larvae make small holes and older larvae chew large ragged holes, and on heading crops they can bore into the head. On leafy vegetables, both the feeding and the presence of caterpillars and frass render produce unmarketable, so tolerance is low even when plants survive.

Hosts include cabbage, broccoli, cauliflower, and kale among brassicas, lettuce among leafy greens, and other crops such as tomato. Impact depends heavily on crop, stage, and the market’s cosmetic standards.

Pheromone traps indicate adult flight activity, and plant inspection counts larvae and rates feeding damage relative to crop stage and market tolerance. Checking for parasitized larvae and signs of viral disease helps gauge natural control before deciding whether to intervene.

Management leans on conserving the pest’s many natural enemies and using selective tactics within integrated pest management.

• Conserve parasitoid wasps, predators, and naturally occurring viral pathogens
• Use selective biological products, such as microbial insecticides, that spare natural enemies
• Practise field sanitation and manage crop residues to reduce carry-over
• Time any action to target young larvae, which are easier to control and cause less damage
• Base intervention on trapping and scouting against local thresholds and market tolerance